Thinking about building a larger home or selling acreage near Boulder and hearing about TDRs or TDCs? You are not alone. These programs can protect open space and also unlock value when you plan well, but the rules are technical and vary by location. In this guide, you will learn how TDRs and TDCs work around the City of Boulder, what they cost, and how to use them to support a smart large-lot strategy. Let’s dive in.
TDRs vs. TDCs in Boulder County
TDRs and TDCs are both tools that trade development potential, yet they do different jobs. In simple terms, TDRs move density from conserved rural land to approved receiving sites, while TDCs add floor area for larger single-family homes in unincorporated county areas.
- For context on TDRs as a planning tool, see the state overview on transfer of development rights, which explains how they shift growth while conserving land and resources (Colorado Planning for Hazards).
- For Boulder County program details, the county’s pages on Transferable Development Credits and Transferable Development Rights outline eligibility, process, and contacts.
What TDCs measure
In unincorporated Boulder County, TDCs function like a currency for residential square footage. If you propose a house larger than a set threshold, you generally must purchase TDCs to permit that extra floor area. The county notes that building a single-family house greater than 6,000 square feet typically triggers TDC requirements, and credits are calculated in 500-square-foot increments. The TDC program page explains how credits are created and used.
How TDRs move density
TDRs are issued when owners in designated sending areas record conservation easements that restrict future development. Those rights can be sold and used on approved receiving sites to allow more units or intensity than base zoning would permit. Boulder County maps some areas, such as Niwot, and also evaluates receiving sites case by case based on infrastructure and services. The county’s TDR FAQ describes rules like the 75 percent sub-area sourcing guideline for transferred units and confirms that unused TDRs do not expire (TDR FAQ).
City of Boulder vs. Unincorporated County
Location is everything. The Boulder Valley Comprehensive Plan outlines Area I inside the city, Area II for potential annexation, and Area III for rural preservation. County TDR and TDC programs apply primarily in unincorporated areas, and intergovernmental agreements can shape how rights move across boundaries. Review the Boulder Valley Comprehensive Plan to confirm your parcel’s area and annexation context.
Inside the City of Boulder, you cannot assume county credits apply. Some transfers can occur under specific agreements, but the terms vary by location and project. If your site sits near the city limit, contact city and county planners early to map out your path.
Large-lot playbook: owners and buyers
If you own acreage and want to preserve value
You can often create value while protecting land. Many large-lot owners record a conservation easement to generate TDRs or TDCs, then sell those credits to a builder or homeowner who needs them.
- Record a conservation easement or similar restriction that meets program rules. Boulder County explains how easements work and what to expect in the approval process (Conservation Easements).
- Once recorded, the county issues certificates for your TDRs or TDCs. You can sell privately or through the county’s clearinghouse.
- Understand tradeoffs. Easements are usually permanent and recorded on title. Conservation gifts can create federal and state tax benefits, but documentation and appraisal rules are strict. The IRS provides guidance on conservation easements and compliance steps (IRS conservation easements).
If you plan to build bigger or subdivide
Start with jurisdiction, then run the numbers. Your strategy will hinge on whether your parcel is inside the City of Boulder or in unincorporated Boulder County.
- Confirm your location and planning area. Use the BVCP maps and speak with county planners.
- For a house larger than 6,000 square feet in the county, estimate required TDCs and sourcing options. The TDC FAQ explains purchasing, using certificates, and common pitfalls (TDC FAQ).
- For subdivisions or higher density, test whether your site can be a receiving site, whether the 75 percent sub-area rule applies, and what review path is required. The TDR FAQ outlines the framework.
A flexible, hybrid approach
You can sometimes create credits and sell a portion now while keeping other property rights for future use, subject to program rules. Plan the easement language with county staff so you understand eligibility, certificate timing, and market demand. The TDC FAQ is a good starting point.
What credits cost and what drives price
Boulder County operates a public TDC Marketplace with active listings and a sales history. Recent posted sales from 2023 through 2025 show transactions roughly in the low to mid five figures per TDC, often about 10,000 to 12,500 dollars per credit, though prices vary by date and conditions. Review current listings and history on the TDC Marketplace.
Prices move with supply and demand. Scarcity of eligible credit-producing parcels, the pipeline of receiving projects, housing demand, and any intergovernmental terms can shift value. The county notes that market swings and program changes are possible, so build contingency into your budget and timeline (TDC FAQ).
Process and risk checklist
Use this simple checklist to keep your project on track.
- Pre-application: contact Boulder County Community Planning and the TDC Clearinghouse to confirm eligibility and requirements. The county’s TDR and TDC program pages list contacts and process steps.
- Document and record: draft the conservation easement or covenant to county standards, then record it. The county issues your TDR or TDC certificate after recording.
- Verify certificates: if you buy credits, confirm the original county-issued certificate is in hand and has not been used or sold elsewhere.
- Watch the fine print: program rules, prices, and sourcing requirements can change. Keep a record of current guidance and build decision checkpoints into your schedule.
- Get qualified advice: conservation easement tax rules and appraisals are detailed. The IRS conservation easements page is a helpful reference when you speak with your tax advisor.
How this plays out near Boulder
Most receiving sites in unincorporated Boulder County are low-density by design, often large-lot subdivisions supported by existing infrastructure. The county notes that TDR-enabled outcomes typically lean toward larger lots and higher-end homes rather than lower-cost housing. These tools can support quality development and conservation goals, but they are not a direct affordable housing mechanism (TDR FAQ).
Ready to talk strategy?
If you own acreage, plan a custom build above 6,000 square feet, or want to align conservation with value, you have options. With the right plan, credits can unlock size, improve marketability, and support a clean approval path. When you are ready to map your best move near the City of Boulder, reach out to Arn Rasker for a tailored, technically grounded strategy.
FAQs
How do TDRs and TDCs differ in Boulder County?
- TDRs move development potential from conserved sending areas to approved receiving sites, while TDCs are credits used to add single-family floor area in unincorporated county areas.
Can I use county credits inside the City of Boulder?
- Not automatically. City and county jurisdiction and intergovernmental agreements control whether credits apply, so check the Boulder Valley Comprehensive Plan and speak with planners.
Do TDRs or TDCs expire in Boulder County?
- The county indicates unused TDRs do not expire. Always confirm current policy and any certificate language for TDCs with the county.
How many TDCs do I need for a 6,500-square-foot home?
- The county uses a sliding formula in 500-square-foot increments above a 6,000-square-foot threshold, so confirm the exact calculation with the TDC program before you buy credits.
Where can I see current TDC prices and recent sales?
- The Boulder County TDC Marketplace publishes active listings and a sales history so you can gauge pricing and liquidity.
Will recording a conservation easement affect resale of my property?
- Yes. Easements are usually permanent and recorded on title, so future owners are bound by the restrictions along with any benefits tied to issued credits.
